Serum Albumin Binding Properties Research Articles

Pyridine derivatives complexes of Co(II) and Ni(II) 3‐bromobenzoates: Crystal structure, in silico anti‐SARS‐CoV‐2 potential, serum albumin binding properties and cytotoxicity

Two mononuclear [Co(3‐BrBA)2(NA)2(H2O)2] (1) and [Ni(3‐BrBA)2(3‐CNPY)2(H2O)2] (2) (3‐BrBA = 3‐bromobenzoate, NA = pyridine‐3‐carboxylic acid, and 3‐CNPy = 3‐cyanopyridine) were synthesized and characterized by single crystal X‐ray diffraction, elemental analysis, and FT‐IR spectroscopy. In both complexes, the metal atom is coordinated by two oxygen atoms of two carboxylate anions, two nitrogen atoms of two pyridine rings, and two oxygen atoms of two water molecules in the distorted octahedral environment. Intermolecular interactions were examined with the help of the 3D Hirshfeld surfaces and 2D fingerprint plots. With the help of density functional theory (DFT) studies, besides verifying the experimentally obtained structural properties, the electronic energies, polarizability, dipole moments, ionization potentials, electron affinities, electronegativity, chemical hardness, global softness, electrophilic indexes, HOMO‐LUMO orbitals, and band gaps were also calculated. In vitro cytotoxic activity of the complexes on primary peripheral blood mononuclear cells were evaluated using the MTT assay. Fluorescence quenching techniques and molecular docking studies were used to investigate the interaction between bovine serum albumin (BSA) and the complexes. The molecular docking study has been used to explain the interaction of complexes with spike proteins of beta variant (B.1.351), gamma variant (P.1), delta variant (B.1.617.2), kappa variant (B.1.617.1), and omicron variant (B.1.1.529) of coronavirus. Additionally, the pharmacokinetic and toxicological properties of the complexes have been computed using the SwissADME and ProTox‐II online databases, respectively.

Antimicrobial and antibiofilm activities and bovine serum albumin binding properties of benzimidazolium derivative NHC salts and their Ag(I)‐NHC complexes

Benzimidazole type N‐heterocyclic carbene molecules and their metal complexes have well‐known biological activity. Elemental silver and silver complexes also have antibacterial and antifungal activity. In this study, silver complexes with 1‐allyl 5,6‐dimethylbenzimidazolium derivative ligands were analyzed for their antimicrobial and antibiofilm activities. Additionally, bovine serum albumin (BSA) binding properties of the molecules were analyzed by spectrophotometric methods, and the details of interactions of the molecules with BSA were investigated by molecular docking methods. While N‐heterocyclic carbene salts showed moderate antifungal and antibiofilm activity, silver complexes of these salts have strong antimicrobial activity with <1.9–15.6 μg/ml minimal inhibitory concentration (MIC) values. On the other hand, carbene salts have better affinity against BSA than the complexes. Additionally, the interaction of the optimized complexes with SarA and BSA were analyzed by molecular docking methods. According to in vitro and in silico evaluation, the studied Ag complexes may be utilized for advanced studies.

Impact of the central atom on human genomic DNA and human serum albumin binding properties in analogous Zn(II) and Cd(II) complexes with mefenamic acid

Two novel complexes of Zn(II) and Cd(II) with Hmef (mefenamic acid) and bapen (N,N′-bis(3-aminopropyl)ethylenediamine) ligand were synthesized and characterized by infrared spectroscopy, elemental, thermal and single-crystal X-ray structure analysis. Both complexes form molecular structure composed of analogous neutral complex molecules [M(bapen)(mef)2], which differ in the central atom and a solvate molecule – Zn(II) in 1 [Zn(bapen)(mef)2] is replaced by Cd(II) in the compound 2 [Cd(bapen)(mef)2]·MeOH. The interactions of both complexes with human genomic DNA isolated from tissues of pelvis uteri affected by precancerosis and cancer were studied by competitive binding studies with ethidium bromide (EB) and UV-VIS titration. The obtained values of Stern-Volmer constants KSV and the values of binding constants Kb follow the same trend, indicating different affinity of the studied complexes towards the DNA samples; stronger binding was observed in case of DNA samples from tissue with more severe damage. In addition, binding of the prepared complexes with human serum albumin (HSA) was investigated and the observed KHSA values are within optimal range for transport in bloodstream.

Glycosylated Platinum(IV) Complexes as Substrates for Glucose Transporters (GLUTs) and Organic Cation Transporters (OCTs) Exhibited Cancer Targeting and Human Serum Albumin Binding Properties for Drug Delivery.

Glycosylated platinum(IV) complexes were synthesized as substrates for GLUTs and OCTs for the first time, and the cytotoxicity and detailed mechanism were determined in vitro and in vivo. Galactoside Pt(IV), glucoside Pt(IV), and mannoside Pt(IV) were highly cytotoxic and showed specific cancer-targeting properties in vitro and in vivo. Glycosylated platinum(IV) complexes 5, 6, 7, and 8 (IC50 0.24-3.97 μM) had better antitumor activity of nearly 166-fold higher than the positive controls cisplatin (1a), oxaliplatin (3a), and satraplatin (5a). The presence of a hexadecanoic chain allowed binding with human serum albumin (HSA) for drug delivery, which not only enhanced the stability of the inert platinum(IV) prodrugs but also decreased their reduction by reductants present in human whole blood. Their preferential accumulation in cancer cells compared to noncancerous cells (293T and 3T3 cells) suggested that they were potentially safe for clinical therapeutic use.

Alteration of human serum albumin binding properties induced by modifications: A review

Albumin, a major transporting protein in the blood, is the main target of modification that affects the binding of drugs to Sudlow's site I and II. These modification of serum protein moderates its physiological function, and works as a biomarker of some diseases. The main goal of the paper was to explain the possible alteration of human serum albumin binding properties induced by modifications such as glycation, oxidation and ageing, their origin, methods of evaluation and positive and negative meaning described by significant researchers.

Inflammation targeted Gd(3+)-based MRI contrast agents imaging tumor and rheumatoid arthritis models.

Inflammatory responses are closely related to cancer progression and several diseases. Anti-inflammatory drugs that bind to inducible enzymes can be used as biomarkers for molecular imaging. Selective targeted contrast agents are expected to improve contrast-to-noise ratio (CNR) in MRI at the site of inflammation. In this work, three new Gd(3+) DO3A-amide MRI contrast agents (CAs) that conjugated to mefenamic acid (MA), a commonly used nonsteroidal anti-inflammatory drug (NSAID), through different linkers, ethylenediamine (GdL1), 2,2'-oxidiethylamine (GdL2) and 4,7,10-trioxa-1,13-tridecanediamine (GdL3) were studied. Their relaxivities were GdL1 (4.74 mM(-1) s(-1)), GdL2 (4.77 mM(-1) s(-1)), and GdL3 (4.95 mM(-1) s(-1)) at 400 MHz at 25 °C. Their serum albumin binding properties were studied by tryptophan emission-quenching experiments, with GdL1 showing a preferential binding toward HSA and BSA as compared with GdL2 and GdL3. They showed low cytotoxicities toward HeLa cells at high concentration (0.5 mM) and high cellular uptake in U87 cells as compared with GdDOTA. In vivo MRI showed increased T1-weighted contrast after intravenous injection of the agents. Moreover, T1 contrast was significantly enhanced for 1.5 h in the U87 tumor model and 2 h in the arthritis joint in adjuvant-induced arthritis (AIA) model at dosages of 0.1 and 0.03 mmol/kg, respectively. Most of the agents were cleared at 24 h post-administration in the AIA model with no observable T1 contrast. GdL1-3 showed superior retentions and intensity enhancements (IEs) at the kidney, liver, tumor, and arthritis joint to those of GdDOTA. GdL3 showed the highest relaxivity and IE at the arthritis joint and is therefore a potential candidate to be developed as MRI CAs that target inflammation.

Investigation of photophysical, photochemical and bovine serum albumin binding properties of novel water-soluble zwitterionic zinc phthalocyanine complexes

The non-peripherally tetra-(1a), peripherally tetra-(2a) and peripherally octa-(3a) zwitterionic zinc(II) phthalocyanine complexes bearing 2-(N-propanesulfonic acid)mercaptopyridine groups have been synthesized for the first time. These novel complexes have been characterized by elemental analysis, UV–vis, IR and 1H NMR spectroscopy and mass spectra. These zwitterionic complexes show excellent solubility in water, which makes them candidate photosensitizers for use in photodynamic therapy (PDT) of cancer. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yields) properties of synthesized zwitterionic zinc(II) phthalocyanine complexes were investigated in DMSO and phosphate buffered solution (PBS). This study also presented the water soluble zwitterionic zinc(II) phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).

Water-soluble quaternized mercaptopyridine-substituted zinc-phthalocyanines: Synthesis, photophysical, photochemical and bovine serum albumin binding properties

The synthesis and characterization of the new zinc phthalocyanine derivatives, tetra- (non-peripheral, 5) and octa-(peripheral, 6) substituted with 2-mercaptopyridine and their respective quaternized derivatives ( 8 and 9) are reported. Photochemical and photophysical properties of the new complexes are compared with those of the previously reported peripherally tetra-substituted complexes 7 and 10. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. Spectroscopic, aggregation, photophysical and photochemical properties of these complexes are also investigated and compared. Photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yield) properties of these phthalocyanine photosensitizers are very important for the assessment of these complexes as PDT agents. In this study, the effects of the position of the substituents and quaternization of the substituents on the photophysical and photochemical parameters of the zinc phthalocyanines are also reported. This study also showed that the water-soluble quaternized zinc phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).

Bioreversible derivatives of phenol. 1. The role of human serum albumin as related to the stability and binding properties of carbonate esters with fatty acid-like structures in aqueous solution and biological media.

With the overall objective of assessing the potential of utilizing plasma protein binding interactions in combination with the prodrug approach for improving the pharmacokinetics of drug substances, a series of model carbonate ester prodrugs of phenol, encompassing derivatives with fatty acid-like structures, were characterized in vitro. Stability of the derivatives was studied in aqueous solution, human serum albumin solution, human plasma, and rat liver homogenate at 37 degrees C. Stability of the derivatives in aqueous solution varied widely, with half-lives ranging from 31 to 1.7 x 10(4) min at pH 7.4 and 37 degrees C. The carbonate esters were subject to catalysis by plasma esterases except for the t-butyl and acetic acid derivatives, which were stabilized in both human plasma and human serum albumin solutions relative to buffer. In most cases, however, hydrolysis was accelerated in the presence of human serum albumin indicating that the derivatives interacted with the protein, a finding which was confirmed using the p-nitrophenyl acetate kinetic assay. Different human serum albumin binding properties of the phenol model prodrugs with fatty acid-like structure and neutral carbonate esters were observed. In the context of utilizing plasma protein binding in combination with the prodrug approach for optimizing drug pharmacokinetics, the esterase-like properties of human serum albumin towards the carbonate esters potentially allowing the protein to act as a catalyst of parent compound regenerations is interesting.

Synthesis of 2′- O-[2-[( N, N-dialkylamino)oxy]ethyl]-modified oligonucleotides: hybridization affinity, resistance to nuclease, and protein binding characteristics

Synthesis of a series of 2′- O-[2-[( N, N-dialkylamino)oxy]ethyl]-modified 5-methyluridine nucleoside phosphoramidites and solid supports are described. Using these monomers, modified oligonucleotides containing phosphodiester linkages were synthesized in high yields. These modified oligonucleotides showed enhanced binding affinity to the complementary RNA (and not to DNA) and excellent nuclease stability with t 1/2>24 h. The human serum albumin binding properties of modified oligonucleotides have been evaluated to assess their transport and toxicity properties.

Interactions of very long-chain saturated fatty acids with serum albumin

The remarkable binding properties of serum albumin have been investigated extensively, but little is known about an important class of fatty acids, the very long-chain saturated fatty acids (VLCFA; >18 carbons). Although VLCFA are metabolized efficiently in normal individuals, they are markers for and possibly causative agents of several peroxisomal disorders. We studied the binding of [13C]carboxyl-enriched arachidic (C20:0), behenic (C22:0), lignoceric (C24:0), and hexacosanoic (C26:0) acids to bovine serum albumin (BSA) by 13C-NMR spectroscopy. For each VLCFA, the NMR spectra showed multiple signals at chemical shifts previously identified for long-chain fatty acids (12–18 carbons), suggesting stabilization of binding by similar, if not identical, interactions of the fatty acid carboxyl anion with basic amino acid residues. The maximal binding (mol of VLCFA/mol of BSA) and the number of observed binding sites decreased with increasing chain length, from 4–5 for C20:0, 3–4 for C22:0, and 2 for C24:0; we validated our previous conclusion that BSA has only one site for C26:0 (Ho, J. K., H. Moser, Y. Kishimoto, and J. A. Hamilton. 1995. J. Clin. Invest. 96: 1455–1463). Analysis of chemical shifts suggested that the highest affinity sites for VLCFA are low affinity sites for long-chain fatty acids. In competition experiments with 13C-labeled C22:0 (3 mol/mol of BSA) and unlabeled oleic acid, C22:0 bound to BSA in the presence of up to 4 mol of oleic acid/mol of BSA, but 1 mol was shifted into a different site.Our studies suggest that albumin has adequate binding capacity for the low plasma levels of VLCFA with 20 to 26 carbons, but the protein may not be able to bind longer chain VLCFA.

Liquid chromatographic studies of the effect of phosphate on the binding properties of silica-immobilized bovine serum albumin.

High-performance liquid chromatography has been used to examine how phosphate ions affect the binding properties of bovine serum albumin (BSA) immobilized to porous silica. In doing this, the time dependence of the protein to reach conformational equilibrium is measured as a function of the concentration of phosphate in the eluent using the D- and L-isomers of tryptophan and kynurenine as solutes. The overall binding and chiral selectivity (alphaD,L) of the protein toward these solutes appear to be related to two types of effects: one being those that are site-selective and only influence the retention of the L-isomers and the other being those that are nonselective and influence the retention of both enantiomers. An interesting feature of the concentration-dependent data is a maximum in alphaD,L at intermediate phosphate concentrations (i.e., 10 to 50mM phosphate) indicative of both cooperative and antagonistic binding effects. Phosphate eluents within this concentration range provide selectivity advantages, and those at higher concentrations decrease the time required for the protein or column to reach equilibrium. A final set of studies has also been carried out using four alternate buffer systems (i.e., borate, carbonate, acetate, and arsenate eluents). Although the borate eluents affect the BSA's binding properties and alphaD,L similar to the phosphate eluents, the other buffers result in poor separations. Observations from this study are useful in helping to optimize separations carried out on immobilized BSA as well as addressing biological and mechanistic questions related to how anions influence the native binding properties of serum albumins.

Effect of Fatty Acids and Selected Drugs on the Albumin Binding of a Long-Acting, Acylated Insulin Analogue

□ NN304 (LysB29-tetradecanoyl, des(B30)-insulin) is a new soluble, long-acting insulin analogue that is tightly bound to human serum albumin differentiating it from human insulin. In the present study, we investigate the effect of fatty acids and selected drugs on the binding of NN304 to human serum albumin in vitro. Binding of the first fatty acid equivalent to albumin does not affect the binding of NN304. None of the tested drugs compete with the binding of NN304 at drug-to-albumin concentration ratios of <1. The binding of NN304 is shown to be independent of binding of drugs in the two major binding pockets that are located in domains IIA and IIIA of the albumin molecule. Tolbutamide and glibenclamide do not compete with NN304 for binding to albumin at therapeutic drug-to-albumin concentration ratios. High concentrations of acetylsalicylic acid and ibuprofen decrease the affinity of NN304 for albumin, but these interactions occur at drug-to-albumin concentration ratios that are higher than clinically relevant. In conclusion, NN304 is unlikely to be involved in clinically significant drug interactions at the albumin binding level. The unique ligand binding properties of serum albumin and its abundance in the extracellular fluids makes fatty acid acylation and albumin binding an attractive protraction principle for insulin and potentially also for other peptide drugs.

Synthesis, Photophysical Properties, in Vivo Photosensitizing Efficacy, and Human Serum Albumin Binding Properties of Some Novel Bacteriochlorins

The synthesis, photophysical characteristics, in vivo photosensitizing efficacy, human serum albumin (HSA) binding properties, and skin phototoxicity of some stable bacteriochlorins were investigated. The novel bacteriochlorins, obtained from chlorophyll-a, have long-wavelength absorptions in the range lambda max = 734-758 nm. Preferential migration of ethyl over methyl substituents among ketobacteriochlorins obtained in the pinacol-pinacolone rearrangements of vic-dihydroxybacteriochlorins was confirmed by NOE studies. The bacteriochlorins show relatively low fluorescence quantum yields. Among all the bacteriochlorins the triplet states were quenched by ground state molecular oxygen in a relatively similar manner, yielding comparable singlet oxygen quantum yields. In preliminary in vivo studies (DBA/2 mice, transplanted with SMT/F tumors), ketobacteriochlorins were found to be more photodynamically active than the related vic-dihydroxy analogues. Replacement of the methyl ester functionalities with di-tert-butylaspartic acids enhanced the in vivo efficacy. Site specific human serum albumin (HSA) binding studies indicated a direct correlation between the ability of the compound to bind to the diazepam binding site (albumin site II) and the in vivo photosensitizing efficacy.

The Serum Reserve Albumin Concentration for Monoacetyldiaminodiphenyl Sulphone and Auditory Evoked Responses during Neonatal Hyperbilirubinaemia

Auditory brainstem evoked responses (ABR) were recorded in 9 neonates with hyperbilirubinaemia. Pathological recordings were found in two children showing absence of waves and prolonged latencies. There was no correlation between latencies to waves and the total serum bilirubin concentration. The serum reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS) was, however, inversely related to the latencies in the ABR recordings. Our findings suggest that the binding properties of serum albumin contribute to the risk of bilirubin toxicity and that, in this study, the reserve albumin concentration for MADDS seemed to be of greater significance than the total bilirubin concentration.

A Simple Preparative Procedure to Extract and Purify Protein G from Group G Streptococci

A rapid method for the solubilization of the bacterial type III Fc binding protein, protein G, from a group G streptococcus is described. Treatment of intact bacteria with cyanogen bromide results in the solubilization of a homogeneous Mr approximately 50,000 protein which retains IgG and human serum albumin binding properties. The solubilized protein could be purified to homogeneity by molecular sieving chromatography and retained all of the functional properties of the native protein.

17] Structure and lipid binding properties of serum albumin

Bovine albumin is composed of a single polypeptide chain containing 581 amino acid residues, and there are many regions of homology in the amino acid sequence, and the polypeptide chain is folded into three similar globular domains, designated I, II, and III, composed of 185, 192, and 204 amino acid residues, respectively. This chapter describes the structure and lipid binding properties of serum albumin. The primary and secondary fatty acid binding sites are located between or within loops lined with hydrophobic amino acid side chains. Two methods have been employed to localize the binding sites within the albumin structure; one is fluorescence spectroscopy, and the other is proteolytic cleavage followed by equilibrium binding to the resulting protein fragments. Both methods of analysis indicate that the strongest fatty acid binding site is located within the third domain. The chapter indicates that fatty acid binding is associated with small conformational changes that allow the fatty acid to penetrate into the interior of the globular protein structure and enable the albumin binding sites to adapt to the configuration of the fatty acyl chain.

Steroid modulation of human serum albumin binding properties. A spin label study.

The binding isotherm and unique electron spin resonance spectral characteristics of a monoanionic spin label (1-gamma-aminobutyrate-5-N-(1-oxyl-2,2,6,6-tetramethyl-4-aminopiperidinyl)-2,4-dinitrobenzene) and a dianionic spin label (1-glutamate-5-N-(1-oxyl-2,2,6,6-tetramethyl-4-aminopiperidinyl)-2,4-dinitrobenzene) are used to prove the steroid modulation of serum albumin binding properties. Effects of a selected number of steroids (progesterone, testosterone, estradiol, aldosterone, estriol, corticosterone, deoxycorticosterone, hydrocortisone, and cortisone) on the binding isotherm of the monoanionic spin label binding to serum albumin have been determined. At the steroid/albumin ratio of 0.5 to 1, progesterone, testosterone, and estradiol enhance binding of the spin label at all concentrations studied. However, the remaining steroids exert an inhibitory effect at low spin label/albumin ratios and an enhancement effect at high spin label/albumin ratios. Progesterone and cortisone effects on the resonance spectra of the spin label bound to serum albumin confirm the enhancement and displacement properties of these ligands. Thus, like fatty acids, steroids may bind to either the primary or secondary bilirubin binding sites and also allosterically perturb the binding properties of serum albumin. The in vivo importance of the steroid-albumin interaction is discussed.

BINDING OF BILIRUBIN IN NEONATAL SERUM STUDIED BY FLUORESCENCE QUENCHING

The technique of fluorescence quenching was utilized to study the binding of bilirubin to serum albumin in certain jaundiced infants; e. g., babies with prematurity, possible kernicterus, isoimmunization, and biliary atresia. Free bilirubin, bilirubin binding capacity, and binding affinity (Ka) for bilirubin were determined from a 25-μl serum sample. An infant with biliary atresia and mixed hyperbilirubinemia was studied to determine whether conjugated bilirubin affects binding of unconjugated bilirubin. While only unconjugated bilirubin is thought to be toxic to cells, both forms bind to albumin; therefore, conjugated bilirubin would be effectively toxic if its binding decreased the binding capacity or affinity of albumin for unconjugated bilirubin. Total serum bilirubin was 700 μM, with 410 μM direct and 290 μM indirect. By fluorescence quenching the capacity was 0.93 moles unconjugated bilirubin/mole albumin, very close to the maximal capacity of 1.00. Binding affinity was 5.2 × 108 M−1, slightly greater than the average neonatal value. Hence, even a marked elevation of conjugated bilirubin did not affect the ability of albumin to detoxify unconjugated bilirubin. A 600-gram, 28-week newborn was studied to determine binding properties of serum albumin in a premature infant. They were similar to those found in term infants; this baby's ability to detoxify bilirubin was therefore limited by her lower serum albumin concentration.

A polarographic investigation of the binding properties of Serum Albumin

It has been shown that the binding capacity of dissolved serum albumin for methyl orange increases on dilution. The increased binding capacity implies a change in the protein molecule. The possible nature of this change is discussed.